1. Field of the Invention
This invention relates in general to medical equipment and procedures. In particular, the invention relates to catheters for use in performing certain medical procedures, such as coronary angiography or angioplasty.
2. Description of the Prior Art
Coronary angiography and angioplasty involve the introduction of a catheter into the aorta, by way of the femoral artery, under local anesthesia. The distal end of the catheter is inserted into the opening of a selected coronary artery.
During such procedures, special precautions must be taken to prevent the catheter from blocking, or occluding, the opening of the coronary artery. Continuous blood flow must be maintained past the catheter into the artery. Blockage of the blood flow may cause ischemia, a localized tissue anemia due to the obstruction of the inflow of arterial blood. If dye is injected while the coronary artery is occluded, the result can be serious life threatening cardiac arrhythmia, such as ventricular tachycardia, ventricular fibrillation, cardiac arrest, or myocardial infarction.
One method of maintaining blood flow to the artery is by using a catheter with a hole through the side of the catheter. However, such a side hole has several disadvantages.
If there is a hole through the side of the catheter, the catheter cannot be used to monitor pressures at the distal opening of the catheter. The side hole communicates with the central lumen of the catheter, and interferes with the monitoring of the pressure at the distal end of the catheter.
The side hole in the catheter also prevents the use of the catheter to inject dye into the coronaries. If such a catheter is used to inject dye, most of the dye exits through the side hole, rather than through the distal end of the catheter.